﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Fighter.ScreenManagers;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework;

namespace Fighter.Screens.Scenario
{
    class MenuText
    {
        #region Fields

        /// <summary>
        /// The text rendered for this textItem.
        /// </summary>
        string text;

        /// <summary>
        /// The position at which the text is drawn. This is set by the MenuScreen
        /// each frame in Update.
        /// </summary>
        Vector2 position;

        /// <summary>
        /// Tracks a fading selection effect on the entry.
        /// </summary>
        /// <remarks>
        /// The entries transition out of the selection effect when they are deselected.
        /// </remarks>
        float selectionFade;

        #endregion

        #region Properties


        /// <summary>
        /// Gets or sets the text of this menu entry.
        /// </summary>
        public string Text
        {
            get { return text; }
            set { text = value; }
        }

        /// <summary>
        /// Gets or sets the position at which to draw this menu entry.
        /// </summary>
        public Vector2 Position
        {
            get { return position; }
            set { position = value; }
        }

        #endregion

        #region Initialization


        /// <summary>
        /// Constructs a new menu entry with the specified text.
        /// </summary>
        public MenuText(string text)
        {
            this.text = text;
        }


        #endregion

        /// <summary>
        /// Updates the menu Text.
        /// </summary>
        public virtual void Update(MenuScreen screen, bool isSelected, GameTime gameTime)
        {
            // When the menu selection changes, entries gradually fade between
            // their selected and deselected appearance, rather than instantly
            // popping to the new state.
            float fadeSpeed = (float)gameTime.ElapsedGameTime.TotalSeconds * 4;

            if (isSelected)
                selectionFade = Math.Min(selectionFade + fadeSpeed, 1);
            else
                selectionFade = Math.Max(selectionFade - fadeSpeed, 0);
        }

        /// <summary>
        /// Draws the menu entry. This can be overridden to customize the appearance.
        /// </summary>
        public virtual void Draw(MenuScreen screen, GameTime gameTime)
        {
            // Pulsate the size of the selected menu entry.
            double time = gameTime.TotalGameTime.TotalSeconds;

            float pulsate = (float)Math.Sin(time * 6) + 1;

            float scale = 1 + pulsate * 0.05f * selectionFade;


            // Draw text, centered on the middle of each line.
            ScreenManager screenManager = screen.ScreenManager;
            SpriteBatch spriteBatch = screenManager.SpriteBatch;
            SpriteFont font = screenManager.Font;

            Vector2 origin = new Vector2(0, font.LineSpacing / 2);

            spriteBatch.DrawString(font, text, position, Color.Red, 0,
                                   origin, scale, SpriteEffects.None, 0);
        }

        /// <summary>
        /// Queries how much space this menu text requires.
        /// </summary>
        public virtual int GetHeight(MenuScreen screen)
        {
            return screen.ScreenManager.Font.LineSpacing;
        }


        /// <summary>
        /// Queries how wide the text is, used for centering on the screen.
        /// </summary>
        public virtual int GetWidth(MenuScreen screen)
        {
            return (int)screen.ScreenManager.Font.MeasureString(Text).X;
        }
    }
}
